.container {
  width: 600px;
  height: 600px;
}

.src {
  width: 100px;
  height: 100px;
  background-color: brown;
  position: absolute;

  left: 50px;
  top: 50px;
}

.dst {
  width: 100px;
  height: 100px;
  background-color: orange;
  position: absolute;

  padding: 50px;

  left: 200px;
  top: 200px;
}



.dst-sub,
.src-sub {
  width: 50px;
  height: 50px;
  padding: 10px;
  //border: green 1px solid;
  background-color: blue;
  //background-color: green;
}

.dst-sub-sub {
  width: 20px;
  height: 20px;
  //border: green 1px solid;
  background-color: lightcoral;
}

.none-pointer-events {
  pointer-events: none;
}

.drag-enter {
  background-color: red;
}